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| Description: Product of two negatives. Theorem I.12 of [Apostol] p. 18. |
| Ref | Expression |
|---|---|
| mulneg.1 |
|
| mulneg.2 |
|
| Ref | Expression |
|---|---|
| mul2neg |
|
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | mulneg.1 |
. . . 4
| |
| 2 | mulneg.2 |
. . . . 5
| |
| 3 | 2 | negcl 5341 |
. . . 4
|
| 4 | 1, 3 | mulneg1 5417 |
. . 3
|
| 5 | 1, 3 | mulcom 5295 |
. . . . 5
|
| 6 | 2, 1 | mulneg1 5417 |
. . . . 5
|
| 7 | 5, 6 | eqtr 1487 |
. . . 4
|
| 8 | 7 | negeqi 5332 |
. . 3
|
| 9 | 2, 1 | mulcl 5293 |
. . . 4
|
| 10 | 9 | negneg 5362 |
. . 3
|
| 11 | 4, 8, 10 | 3eqtr 1491 |
. 2
|
| 12 | 2, 1 | mulcom 5295 |
. 2
|
| 13 | 11, 12 | eqtr 1487 |
1
|
| Colors of variables: wff set class |
| Syntax hints: |
| This theorem is referenced by: mul2negt 5426 msqgt0 5587 discrlem1 6586 sqrlem11 6613 i4 6664 cjmul 6724 vcnegneg 8130 nvnncan 8223 ipdirilem 8419 ipasslem10 8430 hvmul2neg 8836 hvnegdi 8850 hisubcom 8891 normlem0 8896 normlem9 8905 honegnegt 9649 lnophmlem2 9857 |
| This theorem was proved from axioms: ax-1 4 ax-2 5 ax-3 6 ax-mp 7 ax-7 959 ax-gen 960 ax-8 961 ax-9 962 ax-10 963 ax-11 964 ax-12 965 ax-13 966 ax-14 967 ax-17 968 ax-4 970 ax-5o 972 ax-6o 975 ax-9o 1119 ax-10o 1136 ax-16 1206 ax-11o 1213 ax-ext 1452 ax-rep 2683 ax-sep 2693 ax-nul 2700 ax-pow 2732 ax-pr 2769 ax-un 2857 ax-inf2 4597 |
| This theorem depends on definitions: df-bi 147 df-or 224 df-an 225 df-3or 774 df-3an 775 df-ex 978 df-sb 1168 df-eu 1375 df-mo 1376 df-clab 1457 df-cleq 1462 df-clel 1465 df-ne 1579 df-ral 1641 df-rex 1642 df-reu 1643 df-rab 1644 df-v 1803 df-sbc 1932 df-csb 1992 df-dif 2039 df-un 2040 df-in 2041 df-ss 2043 df-pss 2045 df-nul 2271 df-if 2352 df-pw 2392 df-sn 2402 df-pr 2403 df-tp 2405 df-op 2406 df-uni 2494 df-int 2524 df-iun 2558 df-br 2610 df-opab 2657 df-tr 2671 df-eprel 2821 df-id 2824 df-po 2831 df-so 2841 df-fr 2907 df-we 2924 df-ord 2941 df-on 2942 df-lim 2943 df-suc 2944 df-om 3122 df-xp 3174 df-rel 3175 df-cnv 3176 df-co 3177 df-dm 3178 df-rn 3179 df-res 3180 df-ima 3181 df-fun 3182 df-fn 3183 df-f 3184 df-fv 3188 df-rdg 3917 df-opr 3950 df-oprab 3951 df-1st 4063 df-2nd 4064 df-1o 4117 df-oadd 4119 df-omul 4120 df-er 4245 df-ec 4247 df-qs 4250 df-ni 4972 df-pli 4973 df-mi 4974 df-lti 4975 df-plpq 5007 df-mpq 5008 df-enq 5009 df-nq 5010 df-plq 5011 df-mq 5012 df-rq 5013 df-ltq 5014 df-1q 5015 df-np 5058 df-1p 5059 df-plp 5060 df-mp 5061 df-ltp 5062 df-plpr 5136 df-mpr 5137 df-enr 5138 df-nr 5139 df-plr 5140 df-mr 5141 df-0r 5143 df-1r 5144 df-m1r 5145 df-c 5212 df-0 5213 df-1 5214 df-i 5215 df-r 5216 df-plus 5217 df-mul 5218 df-sub 5328 df-neg 5330 |